scholarly journals Experimental determination of compressor map of the DGEN 380 engine compressor using the WESTT CS/BV turbine engine simulator

2021 ◽  
Author(s):  
Marek Orkisz ◽  
Karolina Pazura

Currently aviation focuses mainlly on increasing the economy and ecology of engines. Production of NOx, CO2 and SO adversaly impacts the environment. Parallel goal to minimize SFC to achieve both lower: emission and mission costs. The optimization of components is thus very important. One of the ways of optimizing cycle is doing that based on compressor maps. However it is very expensive to plot one since experimental work needs to be done. The aim of this article is to present a methodology of creating compressor map based on ENGINE ANALOGY. There was used the virtual bench WESTT CS/BV for tests to receive pressure ratio and mass flow of DGEN 380 for three different values of flight speed and altitude, while the rotational speed was changed. The construction similarity of CFM 56-5B and APS 3200 gives the opportunity to plotted compressor maps using the engine analogy without the need for an experiment or using the virtual bench.

Author(s):  
Senthil Krishnababu ◽  
Vili Panov ◽  
Simon Jackson ◽  
Andrew Dawson

Abstract In this paper, research that was carried out to optimise an initial variable guide vane schedule of a high-pressure ratio, multistage axial compressor is reported. The research was carried out on an extensively instrumented scaled compressor rig. The compressor rig tests carried out employing the initial schedule identified regions in the low speed area of the compressor map that developed rotating stall. Rotating stall regions that caused undesirable non-synchronous vibration of rotor blades were identified. The variable guide vane schedule optimisation carried out balancing the aerodynamic, aero-mechanical and blade dynamic characteristics gave the ‘Silent Start’ variable guide vane schedule, that prevented the development of rotating stall in the start regime and removed the non-synchronous vibration. Aerodynamic performance and aero-mechanical characteristics of the compressor when operated with the initial schedule and the optimised ‘Silent Start’ schedule are compared. The compressor with the ‘Silent Start’ variable guide vane schedule when used on a twin shaft engine reduced the start time to minimum load by a factor of four and significantly improved the operability of the engine compared to when the initial schedule was used.


Author(s):  
Sog-Kyun Kim ◽  
Ian A. Griffin ◽  
Haydn A. Thompson ◽  
Peter J. Fleming

Surge margin tracking logic is developed for use in the control of quick windmill relighting (QWR) at sub-idle. Using existing high pressure compressor (HPC) characteristics (but without any gas turbine engine model), the surge margin can be calculated and used to approximate the air flow which is currently not measured in flight. During the QWR flight test, only limited measurements excluding the airflow measurement are available. Based on the fact that a beta value is equivalent to the position of the throttle valve in a compressor test rig, the role of the beta value is here to interrelate between the PRC (pressure ratio of compressor) and NDMF (non-dimensional mass flow) values for the measured CNH (corrected high pressure spool speed) and PRC values. Using the proposed scaling factors (SFs), the HPC map in terms of PRC is adaptively scaled with the engine parameters to cover the operating pressure ratio of the HPC. These account qualitatively for the effects of heat soakage and stability aids such as bleed and VSV (variable stator vane) on the compressor map. The simulation results show that the variable SF approach is more realistic in estimation of the surge margin, compared to the fixed SF approach. As a result of this proposed surge margin tracking logic, an active control for QWR may be possible using an estimated surge margin to adjust the fuel flow. This improves the pull-away time to reach idle power without danger of stall or surge during QWR.


Author(s):  
Pau Cutrina Vilalta ◽  
Hui Wan ◽  
Soumya S. Patnaik

Abstract In this paper, we use various regression models and Artificial Neural Network (ANN) to predict the centrifugal compressor performance map. Particularly, we study the accuracy and efficiency of Gaussian Process Regression (GPR) and Artificial Neural Networks in modelling the pressure ratio, given the mass flow rate and rotational speed of a centrifugal compressor. Preliminary results show that both GPR and ANN can predict the compressor performance map well, for both interpolation and extrapolation. We also study the data augmentation and data minimzation effects using the GPR. Due to the inherent pressure ratio data distribution in mass-flow-rate and rotational-speed space, data augmentation in the rotational speed is more effective to improve the ANN performance than the mass flow rate data augmentation.


Author(s):  
Michael Bartelt ◽  
Thomas Kwitschinski ◽  
Thomas Ceyrowsky ◽  
Daniel Grates ◽  
Joerg R. Seume

Increases on mass flow rates of modern radial process compressors result on larger machine components. In particular, the dimensions of the outlet volutes increase strongly, resulting in disproportionately large machines whose technical feasibility is restricted due to technological and economical reasons. A resulting aim is to design modern radial compressors much more compact, while improving the efficiency and the pressure ratio. Therefore, the present experimental investigation addresses the compressor behaviour for reduced dimensions of rectangular volutes. Furthermore, the experimental setups are numerically modelled and different operating points are simulated with a commercial CFD-Code. A rectangular, external reference volute is equipped with differently shaped blockage-inlays and the global compressor parameters are measured for all variants. Additionally, the pressure and velocity distributions of the local flow field are determined experimentally for varying mass flow ratios at different circumferentially distributed volute layers. The decrease of the volute cross-section results in a reduction of the compressor map width especially at high mass flow rates. Recommendations are given for designing compact volutes of large radial compressors.


Author(s):  
Garth V. Hobson ◽  
Anthony J. Gannon ◽  
Scott Drayton

A new design procedure was developed that uses commercial-off-the-shelf software (MATLAB, SolidWorks, and ANSYS-CFX) for the geometric rendering and analysis of a transonic axial compressor rotor with splitter blades. Predictive numerical simulations were conducted and experimental data were collected in a Transonic Compressor Rig. This study advanced the understanding of splitter blade geometry, placement, and performance benefits. In particular, it was determined that moving the splitter blade forward in the passage between the main blades, which was a departure from the trends demonstrated in the few available previous transonic axial compressor splitter blade studies, increased the mass flow range with no loss in overall performance. With a large 0.91 mm (0.036 in) tip clearance, to preserve the integrity of the rotor, the experimentally measured peak total-to-total pressure ratio was 1.69 and the peak total-to-total isentropic efficiency was 72 percent at 100 percent design speed. Additionally, a higher than predicted 7.5 percent mass flow rate range was experimentally measured, which would make for easier engine control if this concept were to be included in an actual gas turbine engine.


2020 ◽  
Vol 207 ◽  
pp. 01002
Author(s):  
Slav Valchev ◽  
Ivan Mihaylov

Object of the present study is an experimental determination of energy efficiency parameters of air handling unit with integrated air to air heat exchanger: effectiveness of air to air heat exchanger, coefficient of performance and specific fan power of air handling unit. A daily performance of air handling unit is conducted. Effectiveness of supply side of air to air heat exchanger in range of 42.4 % to 52.5 % is received. Coefficient of performance in range of 1.50 to 2.08 and specific fan power of air handling unit in range of 1.39 kW/(m3/s) to 2.08 kW/(m3/s) are received. It was found experimentally that effectiveness of air to air heat exchanger depends on values of mass flow of supply and the exhaust air. High values of mass flow of the exhaust air responds to high effectiveness of supply side of air to air heat exchanger.


Author(s):  
S. K. Roberts ◽  
S. A. Sjolander

Many gases, including carbon dioxide and argon, have been considered as alternatives to air as working fluids in a number of design studies for closed and semi-closed gas turbine engines. In many of these studies, it has been assumed that if the gas constant R and specific heat ratio (isentropic exponent) γ are included in the speed and flow parameters, the compressor map or turbine characteristic is applicable to other working fluids. However, similarity arguments show that the isentropic exponent itself is a criterion of similarity and that the turbomachinery characteristics, even when appropriately non-dimensionalized, will in principle vary as the γ of the working fluid varies. This paper examines the effect of γ on turbomachinery characteristics, mainly in terms of compressors. The performance of a centrifugal compressor stage was measured using air (γ = 1.4), CO2 (γ = 1.29), and argon (γ = 1.67). For the same values of the non-dimensional speed and mass flow, the pressure ratio, the efficiency, and the choking mass flow were found to be significantly different for the three test gases. The experimental results have been found to be consistent with a CFD analysis of the impeller. Finally, it is shown that the changes in performance can be predicted reasonably well with simple arguments based mainly on one-dimensional isentropic flow. These arguments form the basis for correction procedures that can be used to project compressor characteristics measured for one value of γ to those for a gas with a different value.


1935 ◽  
Vol 129 (1) ◽  
pp. 477-505 ◽  
Author(s):  
E. C. Smith

The paper describes an experimental determination of the mass flow of refrigerant per minute and refrigerating effect per minute in a vapour-compression refrigerator, when the state of the refrigerant at the exit from the evaporator was varied over a wide range of superheat temperatures and dryness fractions. The usual methods of measuring the flow of liquids in pipes were not suitable for the present work and a special type of flow meter, described in the text, was developed. The results obtained were not as theory would tend to suggest, but were substantially modified by practical conditions, particularly for dryness fractions between 0·97 and 0·87. The volumetric efficiency changed abruptly over this range from a higher to a lower value. The reduction was attributed to the effect of re-evaporation of. the liquid portion of the refrigerant in the compressor during the suction stroke, as it was found that the higher volumetric efficiency was obtained when the refrigerant was superheated throughout most of the delivery stroke, and the lower volumetric efficiency occurred when the state of the refrigerant on entering the compressor resulted in liquid being present in the cylinder at the end of the delivery stroke. The reduction in the volumetric efficiency resulted in a corresponding reduction in the mass flow, the refrigerating effect, and the heat rejected by the condenser per minute, and in the coefficient of performance for dryness fractions ranging between 0·97 and 0·87.


Author(s):  
Xiaozhi Kong ◽  
Gaowen Liu ◽  
Yuxin Liu ◽  
Qing Feng

What make the labyrinth seal in a compressor stator well different from the normal labyrinth seal are the inlet and outlet rotor-stator disc cavities. Due to the presence of rotating disc cavities, the windage heating and the swirl development are remarkable, which can have a great influence on the leakage characteristic. Besides, when compressor operates at different speeds, the rotor and stator grow differently owing to centrifugal expansion and thermal expansion. Hence the tip clearance which determines the leakage mass flow changes with the varying of rotational speed and temperature in the stator well. A rotating test rig with rotational speed 8100rpm and pressure ratio range 1.05∼1.3 was designed for the test of labyrinth seal in a compressor stator well. A cantilevered structure was used to entirely collect the mass flow for an accurate measurement. To know the working tip clearance precisely, the set up tip clearance was measured with plug gauges, while the radial displacements of rotating disc and stationary casing were measured separately with two high precision laser distance sensors. The total temperatures of airflow in the stator well were measured with thermocouples to analyze the proportion of windage heating among the inlet rotating disc cavity, outlet rotating disc cavity, and labyrinth seal segment. The disc and stator casing were manufactured with non-metallic materials to reduce heat dissipation. Furthermore, the circumferential velocity of the leakage flow was measured using probes to reveal the swirl development. Two-dimensional, axisymmetric swirl flow numerical simulations were carried out to provide insight into the flow field details, total temperature variation and swirl flow development in the stator well. The numerical results of discharge coefficient, windage heating and swirl ratio were compared with the experimental data. Of particular note is, the tip clearance of numerical model at a specific rotating speed was set to be the same with the actual working clearance which was measured in the experiment. The inlet and outlet parameters corresponded with the experimental conditions also.


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